The present invention relates to an automatic equalization method and an automatic equalizer for automatically equalizing the signal distorted due to intersymbol interference.
A well-known type of automatic equalizers adapted to perform maximum likelihood sequence estimation is those using a Viterbi algorithm. The automatic equalizers using the Viterbi algorithm are disclosed in, for example, Japanese Patent Laid-open No. 7-22970 and Proakis, "Digital Communications", McGraw-Hill, N.Y. 1983, page 410. These automatic equalizers perform the maximum likelihood sequence estimation by using the Viterbi algorithm. However, the automatic equalizer of the type described has a disadvantage that the number of arithmetic operations increases due to the complex Viterbi calculation.
Therefore, an object of the present invention is to provide an automatic equalization method that can provide the maximum likelihood sequence estimation with simple arithmetic operations.
Another object of the present invention is to provide an automatic equalizer which is suitable for the above-mentioned automatic equalization method.